(a) Field of the Invention
The present invention relates to a device and method for measuring distribution of atomic resolution deformation, and a method thereof.
(b) Description of the Related Art
The development of nanotechnology has had a ripple effect on various technology fields such as biological fields, energy fields, environmental fields, information fields, and the like. In application of nanotechnology, importance of a method for precise measuring of location and deformation in a nano/micro structure has been highlighted.
In general, a transmission electron microscope (TEM) is used to measure deformation of atomic scale. The transmission electron microscope focuses electron beam and irradiates an electron beam to a sample, and enlarges the electron beams passed through the sample to acquire an image. That is, the transmission electron microscope measures a defect or deformation of the nano-scale through the atomic lattice structure. The transmission electron microscope is advantageous in observing an atomic structure of a material with high magnification, but it is difficult to manufacture a specimen that can be observed using a transmission electron microscope, and manufacturing cost is high. In addition, the transmission electron microscope cannot observe a large-scale target, and only measures a shape after deformation of a specimen so that data such as deformation rate measurement cannot be easily acquired.
A scanning probe microscope (SPM) is widely used for measuring a nano-sized structure. The scanning probe microscope includes various types, and a scanning tunneling microscope (STM) is the first scanning tunneling microscope that scans by approaching a probe tip made of a rigid and stable metal (e.g., tungsten) having a pointed end to a specimen to be measured. The second common scanning probe microscope is an atomic force microscope (AFM), and a small bar called a cantilever manufactured by micro-machining is used instead of a tungsten needle of the STM.
The AFM operates as follows. A probe pin (or a cantilever) is as thin as the size of several atoms, and an interaction force is generated between an atom at the end of the probe pin and atoms in the surface of the specimen when the probe pin closely approaches the specimen surface. The interaction force is usually Van der Waals force and is as weak as less than nN (10−9 N). However, resonance of the cantilever is changed by such a weak force, and a degree of bending of the cantilever or a variation of the resonance of the cantilever is measured using a laser or a photodiode so as to measure a nano-scale structure such as a curve at a surface of a measurement specimen. In detail, a method that is most widely used measures displacement by measuring a laser beam transmitted to the cantilever rather than a reflection therefrom using a position sensitive detector PSD (or a position sensitive photodiode detector, PSPD).
The scanning probe microscope is widely used because it can easily measure the shape of a specimen surface, and unlike the transmission electron microscope, a specimen can be simply prepared with a low cost. However, the scanning probe microscope has a limit in measurement resolution so that it cannot measure an atomic structure of a target.
In measurement of such a nano-scale structure, various methods have been disclosed in various points of view for improvement of resolution.
Korean Patent Publication No. 2006-0024470 (“Methodology for nano scale material joint and welding using Scanning Electron Microscope”, 2006 Mar. 17) disclosed a method for enhancing a circuit structure of a probe tip current to maximize a discharging current for improvement of resolution. Korean Patent No. 1060506 (“System and method of lithography in atomic force microscope and for generating input signal to use on lithography thereof”, 2011 Aug. 24) disclosed an algorithm that realizes image lithography with a raster method using a scanning probe microscope to improve resolution. Korean Patent No. 0496457 (“Head of atomic force microscope”, 2005 Jun. 13) discloses a structure for improvement of an alignment structure of an SPM and PSPD for improvement of resolution. As described, various methods for improvement of resolution of the scanning probe microscope have been disclosed, but none of the methods provide an effect that overcomes the limit in the scanning probe microscope.
U.S. Pat. No. 5,540,958 (“Method of making microscope probe tips”, 1996 Jul. 30) disclosed a method for manufacturing AFM probe tips respectively having different resolution to widen a measurement available range. However, the method also cannot overcome a performance limit of the scanning probe microscope.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.